The subject matter discussed herein relates to a data synchronization system, and more particularly to a technology for maintaining the data synchronization of applications among remotely installed distributed data centers.
Recently, to perform disaster recovery and grid calculation, there is an increasing need for data synchronization among remotely installed, distributed data centers, which communicate over a network, using data synchronization servers. On the other hand, attention has been paid to, and study has been conducted on, the “network virtualization technology” used for building a next-generation network. The network virtualization technology is characterized in the guaranteed quality of communication where a communication delay is taken into consideration and in the efficient use of network resources achieved by changing the bandwidth of a virtual network.
To achieve efficient use of network resources, the methods such as the Priority Queuing (PQ) method and the Weighted Fair Queuing (WFQ) method are conventionally known (see Chou Kenjiro, “QoS in the Internet—Control technology˜Diffserv”, Internet Week 99, Pacifico Yokohama, Dec. 14, 1999). A delay reduction method for use in a wide area network (WAN) communication where a route is selected for each application is also studied (see Sawa Yuta et al., “Proposal and evaluation of delay reduction method in wide area network communication using route selection”, Workshop 2010, Institute of Electronics, Information and Communication Engineers, Technical Committee on New Generation Network, Aug. 17, 2010). The related patent documents are JP-A-2006-245992 that describes a communication device that reflects the delay time of data, which remains in the buffer memory, on the communication control and International Publication WO2010-109767 that describes a data synchronization system that calculates and sets a network path for connecting synchronization servers, a bandwidth, and an allowable delay for establishing data synchronization between wide-area locations.